SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91a353535167927b995a73c0ffe0b54d9bbf4998e4f3e8c7a2735f833c4096f6' 
  AND token = 'P8jj/bbWaOCcJxp3kQg/gpuZGPZE6vy/oClPVsLmlWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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