SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b116938a976b60d7ecfdbbcae39d2230e7e7a4f23421b12e078d21f3a8fbec1' 
  AND token = 'e46IniNZLChliuzhHSAjlTH8PzZ2i5UGgiI+eQDyelk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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