SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71983854ce7d5362191178d4654922ba4845b3bd5a118636c302e21f8b238d91' 
  AND token = 'VJ+9SS34OClVOxwV5feUruNspzHkWVlzxB3Jti74Riw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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