SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76a62362ea1a928d18b8db583997fd1b5eff035924165c423eb4689ad579515f' 
  AND token = 'GITiBKrknELlJtaS2hVnvCBCEz0yV6Q8KLJhQPM+urg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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