SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9eac1c28f6b88cf89d114f9354ee6b7ea4c66a63a494539b5398203cfe4efb21' 
  AND token = 'ulvG3f/hEzXOyRZHYwJKApXM3KhaIIBuhEyyGBKDbWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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