SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bcb628962d71666a1e84ea48141764cfa186a4bd928b6e784ee3cd51e5e5ec7' 
  AND token = 'WFKGOKHkCkkDG1KaaD4ZprI07hJFr2LCSv8tUS/5hQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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