SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d01bd36f21c216b4b0a0744ce2d1d56372b2ead2b829ede88739b192f3f6766' 
  AND token = 'Mqp1BZaiC0iJOPVF+wvBFZumQKjY+UksdbSFsS8weiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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