SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6a2b8125aac40d0c1ff754896cbdde3822bcc9753f3d7a66582f30cf4a0ba1d' 
  AND token = 'ztajOZStBF9QpCBOt1KH3JN05drDQknNGcGHom/Ghgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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