SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8186f7e01375fe26a61e4f5514818f57bb4c9283552ce754720df021a669e8e4' 
  AND token = 'Ulyl5J20chHSTxXjn+z7V9YLUsB6lVCInSVr/sxdNOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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