SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12c56c03220cbc0b06a634a62e87f26b600c90faee7f83d6dd6317c0da342f2b' 
  AND token = 'wYnIPm5HOfiXa7rPvPOIyresRUgyBkoHoy1poFXiVBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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