SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e038786fc6c9f6080227818092675c1f983658dbc084c5bb822ee4660f84c365' 
  AND token = '4PXRpbmwz/Xr//GxTOKKh/ZBuBz1+DwCY+u2PuKdh4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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