SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e04e32154325019bcc31a73ea0a29901da3207edf08391e3456384f939b90f2' 
  AND token = 'CpYZ5WhDzbBgJMa+t+aOYKbj0FmDwdJBbQ7XfU4Gij0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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