SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f9081aa3484ed850e9c9ebd6c77f7fa290bd518742ceb6350d75cf6e1fde2b0' 
  AND token = '6d2oJ6mCPGt0+yXOVKuvoT2wcppBUGAxnqFaDuy0SLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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