SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9402f6a061733052657fff4bdf9a3e60724870b3c22e8878823269353db7db4' 
  AND token = 'ewP5LiClWElZ5JcRfych32LK8+nwFUbF+LoFbcCyktI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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