SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '624dbba247ef1662e54247eac55e3cb7e8ecd1c0d27a6e36dd12550526815778' 
  AND token = 'a843yqHPaNVcUIKu0yoC0iFPXklymxxUPteVJDxaKO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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