SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '682eda16fb46c19816d3b72a6685b0511c8449f25bc18066492f7e78a267507d' 
  AND token = '8fDjUFc3p2xuING+vfMu2Ap9+N0oqwh5SClOECyDhZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}