SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff4c391e0af66bc797537fbcac248772968756a2d178deddb0a8401ec728f380' 
  AND token = '/WGYd3nhvr5xx6Q1ZCJq3i8PPqXNBdjqnocfHr/qXMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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