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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '761f04f3ffde3d183d9bdb37e1c1fa209d916a771700c8b49624bf1209fcd360' 
  AND token = 'hUH2NN8nfBVlOrSpDtfdnV+RlPZEiSaQVyoQ7VLk3FA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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