SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b5ff96887c4863eb422bc5a3205a1671982ad14c34f96c764201a3a964cac061' 
  AND token = 'WGm5npCNMY6QG2coaMheGlEmEDn2FDBFJC1qUj+g9Kg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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