SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3c8bddf1b92f2508e9d56df730d60aaf1777393e0f31a3e3bbfc15a077c342c3' 
  AND token = 'EGE2GUhBOQhX+78sSCE/mUf1sCS3R0aUqvL5gEz8wIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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