SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f4162120709cebc4c5554d6b800a7cbd541af612b88a2dd499ef85804bff4bb' 
  AND token = 'dk6dx9jARvdOLty+R8m6PTqHFPOQxK2S0lIICGWstqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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