SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a77ed92aa909e3fcb20cc2fd88f0400bffd2656f4698bc8434cccb39c2b8ff61' 
  AND token = '6BPA8pc0318BD34A6NuImZrljeUBqxHMmyK27pU4wJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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