SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db9d5b1a03006f815560fc8a40eddb46373b5064f52243e3e30781b72edfaad6' 
  AND token = 'yGwhrZubvnofUZSEB/NtxA6gPrpKQ8/SNkugo6UYVd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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