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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82e99d076d6e4752dc3cc3e3f53581dee496bcfd2022a7b4dd78e2ccf0dca24b' 
  AND token = 'D2bkEzevR9mOxkcvNGqWWI9u/a+4GUG/zDc67KgWPjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}