SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52681ebaaa645b9418b4944621c1b0a4a987ec67d360bd3e8d29303b362cccd8' 
  AND token = 'deZJUFYZtKjDuB5L0iyV5CpmQyxo50Wdc/vQRV8MDu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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