SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd27a70fc042dc6c016d1496bcef6874e92c1b46bf6c6b836734350a93a5a8069' 
  AND token = 'jcWjZiGnNPxfomXeD2obTP2UtY56NUKSkD9fIcKq7Ow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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