SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '51b196b84f7eee7377b1a3d5e1dd2785c8ca49085a2df93332e22de2e38cf8c2' 
  AND token = 'fWHW/Up7CgzM6NOZh7oyvMkGKJnXPmNG3Dxh/bwdQ8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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