SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '690f0a18076bc395579e3a8e2192e167348cb46e0af2bf4245b6861fb321b6c7' 
  AND token = 'qZjqa/wkkDBWRVUNCiDLmZ5GszWGTdw36IZ6cxsZAKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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