SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '109785c3dfbe5ad41e618e41df7d8a3dee6043830541ca2c6275d019589640fa' 
  AND token = 'xlRS3m6XwDWiYmkUVkRkhrlIwsDb6Eww4Q6GDAwU710=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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