SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab757e70e74813250e37c8900158abafc5756714b4a582c0b0046b071efa2e78' 
  AND token = 'D8hNQSpWwfZqgCLiw17dunuHZ0Q3VgScEIMV9KkUKxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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