SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d96181dfa0d54b1338d4e92436c5dcc7a2b878ce3043b39ee7f56e70a5f2b5b' 
  AND token = 'Sm2DwYiZ3VgZQ+ZZC/T51zQ0JUxZ9ik6VXGBrBR8WRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}