SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '108d63572a52a039b09c1ab5c2358172810cfa4027d27a7e0b159a7965648a50' 
  AND token = 'f3jW/S01pbMOOulS2CQnwJG3lbcxTOeMRKEDwzvdhTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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