SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e891490da836145bded001e142de8324c40b8c0a1f9fa4293f8b733fb587678d' 
  AND token = 'JXSZb1NHBpSX20fgZ/mttWOUI78ZAGlRVqgCw4HQ7Es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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