SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f592f81a07586dc7b6385a9a87bb80bf21b371d7caef4e5c0cba142bb91237db' 
  AND token = 'JyG4VDWXAy57EJFxQelq1N/Fi4y4O/YMqZf/1IkP//o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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