SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37b32a57d58aaa9157d27103416d5827c589838b39cf6580f2da2aa1a114fdb3' 
  AND token = 'aJ7lkiPGD6/uTwBbEazXCxu0hK1iVQ9DiXufQYbvibc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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