SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92b09dbd62595c7dfcdad9c9fb6cb239980a56bbfb7f3c428262ada13cbeea23' 
  AND token = 'mwImbQSXlJUju8B87lA2qKUkmC3R8GWkiuCbcG715ZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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