SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec9993e99aea2a47cd3e5bdf4dfe7f45f050e26bf00a8e7a7ed9c771d474517f' 
  AND token = 'TmjnlmPhO2zOJ/HTe7sLLrW2c4z23ecXhwbpZE5JphA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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