Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21eddd2646c6d21fa7048e71afa749cb387e0cd0644ca6409b2595a98f80b1ee' 
  AND token = 'z/JxzauB7+0MOm7eF6+aRsVPqnO/UVHjiMX2rMbPXac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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