SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e4ea2329ad29ed337417908837556cb46eaf39551ca3d0979afd91793a3799d' 
  AND token = 'vXFM8KrIRYRiBNiaOwnVjgvkGSnxJKIZlBEqEJxj/Cs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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