SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c75e84a61295e99d09f40693af737cea5ff545fdbc440eb4baae95634ca68578' 
  AND token = '/5rp9elcDb3cV3JRc8e9J56NQKXliGV9ptZE4n8xoag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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