SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef0b0e41e70ce5797186312b5efdb9dc39e74555095c06ee0927cd9d8b667087' 
  AND token = 'aWQnLlzTtm4B1QPnEkWoih1MblBchgxFYWO26O65QMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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