SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f3757f42fa9d1d1aac06d902a6aea99864341dbe285f319230acc5b237c0bfb' 
  AND token = 'OFwOLVthZbSTsrDAVuMXzgH1NyHLQSxOKFKIgdNFBc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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