SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70c03c13b523d3a79d8c7f7eb28c5237adb7c98483199d30566ebe8a3915cbd9' 
  AND token = 'yT8hxH7FfvDPEQwCv918ZqqmPgOh+6TYZ+R3W+aljng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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