SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2321a5e8906c8621bc19340f5e6d7abfdbcb0b5318d4731034f473ac45c513f7' 
  AND token = 'hQo2zTwlreBO/dAYrYdEJ5JCKr0gTtQbXgR1leIzHGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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