SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b17f809cc849184b06d05bfb31decf23b13d59b18901c1708e96bf60ac2852aa' 
  AND token = 'eYm/Nm5AQDjoddt63uGQcB7BWbi8Uq7zhkE1WwOSxA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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