SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d2299b916b17a2e1e23adcc111025426e61fb42b5d333c1febb78e49226f8c9' 
  AND token = '2gYVdI6rrTleRrndzrJWKRRIbq+pFWPEYcTB28XuO64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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