SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c0c2319223d4ce9cba27190d99a1cc4430bb089b4909251681358356e490227' 
  AND token = 'uOrAzvI3LGwubAZImE4EZ2TJXLL4dLBWPXp9df/NBtE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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