SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6564534cc4b5dad94c462f5452e2c14d85a78cebd455859c309c386941dc35f' 
  AND token = 'ZnKJ7UpbVV+L+dY2RtVXOolMOll51vEboL6NWXKHFRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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