SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96f89849ae327c92db37cc48078e138f1385680a597ff4d8d6976ff662a65192' 
  AND token = 'MOVQFAho1Vr/Z3qol01e9S+IvBl5P+qQxhbDKgSyW7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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