SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e8765841ff7ad285a9b7bfe78cde2d02a6d16115ef700d0195dc038d44ceb0a' 
  AND token = 'kmYrgD9GQRWdvSVqflWxsVpTJJ5i71XRUPQdyxCtjjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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