SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dbeaa6b2a7f76307ffcc052a5a15f3aee7df1eda03a698d0594b650105124f4' 
  AND token = 'bY6VCR+LGST6/7MmX5hKOwVn8AR+lmIclYhENP9lc9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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