SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ccedc9853aded4bd835b2ef59a636cd2db20a28c99e3abb2ab6f787e969238a' 
  AND token = 'xUTY8VEp/61WsiMiQ7WsknfAAjTKA84pluJL7jzwCsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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