SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5d575673cf4766b7f51979a40e41a752164abc1af097078450061815c43f3852' 
  AND token = 'oZzoQcKlMbvACBP/Ov9XLrj1gEhVk/BTYgZRC+YGInc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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