SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '873bf69621e29ec150a037515aaaaf111308e8c87c03d9adc9e65473229bff8a' 
  AND token = '50bnbVFvbjSA80iOKVYtJO4g+K1gD3N/ovN0qt3O8B0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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