SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b58f3173b98d2b157ea97392840b9ee1104e0d5378f82e76f2a8566a14914634' 
  AND token = 'A/cODaWrQHc2VPvkEISUtqfcwpRsHoxGZafZi+cot5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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