SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8856194c9d63cef7155cd62351d5a2f93bdc94ba26272174f54faa99576f9c10' 
  AND token = 'oOOo283itrAnx73SxsOMVYpOIwTlh3zYw2FL4Dz30KU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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