SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '29d8e116a9a1e120a1136e447eb5789d7d1e9277121da5439c2b35c6b77036e8' 
  AND token = 'RHu47E2WLNeN2ALmGH+2zCu5LYyB4x+DhP9STwewzXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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