SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b776bfb0fcb2d5216b877fcaf74b136263e3938b0cf673bc8d7a0aa54a3b72b5' 
  AND token = 'yKtsFeWu9isUbLIti2BTur1rDiqpgtyF3vNbRCu7SCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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