SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6df20ed5bf32a2f3715452c85a5073f075b9f8099dab76ce5b0ca3c3e709a95' 
  AND token = '9OrStT72B4DRQwOJfIsPgBzzc3ePC9qhfy01z6EVxxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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