SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8a34d5a91c479c9f6232ddb1c8a1791477522ad7b714f5a3c01e5b84adfcb061' 
  AND token = 'kmksS5ulhcuoOHW91zRoKJ9+VVeByuiHRPh+YO1UIMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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