SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2390c648ff0b0376b48d06756342a830cbc56f477c4c1d4b9abd04b758c01e48' 
  AND token = 'tb4Ria9+xTAWuyjuD0INyKNtBAhM+qouVfnbP7iiCrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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