SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3558b3a43a745beb6fb76013df306ff891c4c0da44cac3bd3a8fae32de6e4720' 
  AND token = 'dsQgG010NjhLtNn8SZgAGFjKgQhQZBIHrMQROhxWDQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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