SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6d7682c4481a665dd8329d49c1357812d50e4b7d5641309a8150f0d768bbb577' 
  AND token = 'pcYvQiaMWGjmShrUuhg4L2bTzND8vxVGME70EiM4W8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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