SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd0ccd6025405d3944a4fd0b4909be096c269e662c0e6daa157025c00c5a1196' 
  AND token = 'nF2nUOuR5lH9iZKAbIt0YRnwUmohx3SPqLXRi4nqCSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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