SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bc2d58da9812acbc62e75d6a425846a9c4584a5fe5a6862609024362bfde08e' 
  AND token = 'KzFAKubFk85dsv9IGJ90iunzjYtJ/HxxCKZ4sZXwDT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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