SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2b9dedd9443ea7a68d3f5c9b9aa13537d627bf8453cdc4db17e59a8c1ca7fb8' 
  AND token = 'lzTi+pxRQ/Wn/pZn3jJ14dWMj8FLVVFtJtKXD2ypq2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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