SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '94aa618f3c60f54316f5eaabbc750905e54399a21f6bc869284a12cd03d65615' 
  AND token = 'b7B0FEOmMMZulS/CKv4498g3Zrj/XVkEhUcUqAitGpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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