SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efc08a109b4fcbb53af309d29e63915d598616f8f2bd0310ce5ccb4710dfe397' 
  AND token = 'qUPUVa4qyURppfZLiJQ7rTdIV0E4ueS9IXdVhqKL/LE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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