SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f415437cf6ee3927ec64f0cc18ab6b81c6f809ed3331e1d85494640d165ad331' 
  AND token = '9meHwRjYF5WqraKv9QFQMHxAQ/BpFO/wt82XIkWYVwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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