SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b770b693ba893255723d0335f89ba0785cf950b2089a180e0d39c7eb2c6ad1b' 
  AND token = 'fLa7NbsJPMn4F99hG8hJ+GG6Y2yw01+Mr3od9zrZbG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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