SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fb6d4291de2ece581b731b1086519a6cb8ae471ed53833866413b8f3670ab67' 
  AND token = '4xGrSPehXAgwM0dMr6fVtXTQS/aR2ruoWBycqMvI6uc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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