SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3cf7a21e30796021ae0cccae38eeb1df2cc78b8c815e029f2ce8276481b74df' 
  AND token = 'Lj0PYHh0K7icwffhKgFRtDoHDles65uEwUiQfElZedA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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