SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb6ac92536f9ea6768a4156f2f873bcfa3efd59ad9947641dc017ce3bc37d516' 
  AND token = 'BNmDCUkPFscMNJKq/t/ZrxPmjlpA2xgL//3gua5R7vE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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