SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9f58921b95365e71bab8f43bca0c673dd797fb6585e5ba15b99de37fd0b8753' 
  AND token = 'IVsvV9iqHpwUXmQ/iMrS1OXAoYX3i3XiQfYTMdls3vo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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