SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c299055cfe1524d6c1e11112c014c0efe7f8adc2b5851976081308664aa2b74f' 
  AND token = 'y70KWqbaHorh5FLOd/Zq52ApouGUTGTY/EAKjzABDlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}