SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7c40106c794e648fe64eabab9eff7a2a2f565fdbfb370891064077db041c88f' 
  AND token = 'QyDSSTaUGB/eQC5egnup46qenE8h6x8tCLWxjKgzMFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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