SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba74c5294af6c8431da8b9518bea96f41c700082a4d51a78781dce83d721bf99' 
  AND token = 'WjqwL5b9IWTxPPHz27u9qnQDD4b4hBCbozptoOBMlOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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