SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fef9241d30c81132e599a75f95dd09b169c43f197a88f26a5d1b596308cd0a34' 
  AND token = 'Y2E4UBIjv8PZzXFXMdgW83qDXKRB7DdVhVCX+zNGzXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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