SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9361003bd88ff36fd8d93e6fd72a9fef0b067ae96de459ee4c316dc36635afd7' 
  AND token = 's/PjbLY/ikfn7+6NhiI0hJhQLPCxTZV0f4sQNIHy/k0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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