SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5cc9decf71af6f2180be08efa303f761384372e6b9ad7261b67811d013f1768' 
  AND token = '/nsRF9JaaGmHrXHaPY8a8v/4AwWMfLzAR2UoSgcolWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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