SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fd477184210e845823e8f3b5c8f103f9fbfdeb5ad3e87ae604560d7796819f8' 
  AND token = 'eXPfUuj0fuhNW5ZWE2x8fkJyPS8rq6dsRIVcb64wSrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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