SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2040ddee7730e94a1718d51e148bc4cbddd98302e7c6f085420a89baa26cccc7' 
  AND token = '+YVgDHcROtHLJO8CYz9lRFU1lqeUkyisf2fPgb7SMyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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