SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94eba8fb75b0a86886bcb5628e323fbe96098ca6f07a87b8f3e44a8c6ecfbe5e' 
  AND token = 'CZDs+LH7aOJ4XdQnQ6xUlbzaWnvcGSZB1Z1GHVu2VkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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