SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '892d759dc9579fc363053ada6e2e18eafe70870f3026aeff00c46eefe5552805' 
  AND token = 'DdhcmIL/zlcadkfRvuuyONktbh24ug9h4N5DyGLbees=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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