SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8629a4b0ab2f5444156d7eca5a362a0a4a5dabee1ee769333cc236d43ca2420c' 
  AND token = 'VfOrzKGnVKB3KWseV4MkSN+QDHqevQif+L9skq2scSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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