SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af56b202a935c344074516d64918c6f39d716d010fd024d7bef290a5bd154c90' 
  AND token = '1fqhfm8nqLpbD2LeIFa68x7vIS+oGGkWH/OvMzbxe0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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