SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a36cc05e21e8294a93004a11a796a2690b2e7f2a1f87beab6116f9913ab5a80' 
  AND token = 'TbqXCDmNrVn1HP+yCbluWzLLBysuIMXdr7xBP+krAp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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