SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad12489a677bb94543d0f7611c4b8dda1c33c1010c061380cc3a457f355beb7b' 
  AND token = 'xdQoxRPQkHGGCJ8l+KFG9kVSJpipl/EIFxwN5gnXO8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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