SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5de6fdf4704a67fc8133312e50f86c5a41fe977fcddbf5bdcaed0ac3bf8b655' 
  AND token = '+/luBFIwvt5Tbno8nKgYQFM3Y1983m+spWBjyoOV/TY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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