SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2d8fa752c350a035539f96dcc35b2054d85beebd9b78fd1da9d35b378d841d0' 
  AND token = '+e9k9NCNufnQF7TSYlzictiFfm/0x469a9hJt+/JyZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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