SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ceb8fc423af5a667fc67aa50c1757cb921b88de1122a2781e899017252e63fc' 
  AND token = 'F6XCjEUMLMaqt3ncwyf5FEVbSJzthpLj8m3aB5fuj48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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