SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '54cd2a6cb50c77c1ac5031d9fd8d884ddb13ab23c9eb46d8abb7b10c2f876ac0' 
  AND token = 'lSWuJ+b8Dlfb7HN58u42gIP3ZChLTDQMVHw536/7F2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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