SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abc9923e8d56638d86a5480fe253477eacfdb0ddfcc77f36c98a8b1d790437d6' 
  AND token = 'VzWAn7JnjOGELOSMIDHc6fQMZukedudOcvMRm5POSL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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