SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a64e28231f063af168ea92072e512572ed571d8330f7d5ff9b5b43b5b1ce90f1' 
  AND token = 'X7sMyEPr2s8dpdbg3oA5OkQKvrDkY6tF1nG/eCPniPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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