SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4232bfd1fcc8f54b18557c251a194ecd79bf2109de4fdfa6c13e4aaf66ce0421' 
  AND token = 'NTIAVqZzKVQR/tJz5nPtv7CK5NmYclmtOZN1jVI6V1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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