SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a3d8d85efafbe293ac0cea2384d4c14b36968fb4a05f427dafa5228465a46ef' 
  AND token = 'LWOvWwel5lmNHzllyAVlogLfSFCCwgi7TJ39IaFUMPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}