SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25754c09945841a3572f20013ab4b3c568e85fdd480db8a4344813be8c69c0c0' 
  AND token = 'otRl4//IrqIjTxECWbqMdsxWo0cyAecM8re1adGWFro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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