SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59c3c84df9c41bfd615c683c1bfb0fd0b602bdfda791161252f3d1afd14503ce' 
  AND token = 'pLjv/nHcxIO5cbAKrTzfl7GWDJKp+rVLQj5pHCT6u6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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