SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7da9fc12297766092aad4a72824a8396ec3925732750c88bbfe36686d2cc3ead' 
  AND token = 'E519HTmP6aGXu8ygb+SMbZyu6Lr/8Ihqb8uBN0/sgtg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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