SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87d34aec84e8eec28703a446bf60e356284fc3a93dc12ce3814ba3396c95407a' 
  AND token = '/7RKMUgBZWWBgwwC5fMcKLZn8UFwTaelcOS7dcihuBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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