SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6f510a0a6a7024329d5cc9c4c33f558895d2a729c9e8fc7c3bf72c3820f65deb' 
  AND token = 'MhzfkCnxtF36xQCFzdMJEhnmcvsOolVGhiiTud/SGH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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