SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c9ea3be77e5db9f630c07cacd07f6197e0ce7fdf3e437224a7b03ff318f7a34' 
  AND token = 't01QMdpygWOsPoHNuSPqLaAISuYcOtVPodwigQJ29fE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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