SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '705d04e3497a5fdc854ab876983925a6c23f08944324bb754ad2ec06cd13a7fb' 
  AND token = 'dlfHNXJ1Q+WeqVna9vKAg/Dd/Y7+ilPvAhUXhbWYRr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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