SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85cb348facd73d9b9eb1b6bf046822a3e496d5c8a21cdb0255d749f9665d8ca4' 
  AND token = '1diog1wWUolALKEUK4Ssb8t8bBOLw/ViIa3Na0wu2eQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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