SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfa20425f5e8c99421e5113af9c92610e98d236ee19752469a22ebfbfa88b21a' 
  AND token = 'Fgzjl4/i4U/0ySu51ufaJG86fRU+XCReGL12QkOpvN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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