SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '760dc13caad16afc96b0af935f9650409f6834879cd2a7b7b95967e10833b4ef' 
  AND token = 'xQKnCjoHQXxq4EVjhKcq+HrXXmm15k7ZBGCPEIl9YY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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