SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23684eb48eccba90351c996bdb5bb60769d6c8f2d299c82e9ce1a2f85cb89ce1' 
  AND token = 'paQDitsNCaWxC3zxgwho7oDzBoBmDy2AGIf2TGtxecE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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